From Derek Thomas
Laurence Jay’s fishy sweets
(This Week, 13 February, p 7)
are very similar to the “bubble sub” found in Jamboree bags of the 1950s and early 1960s.
The small plastic sub, 35-millimetres long, was hollow except for a small
round reservoir at the centre. You tightly packed this reservoir with baking
powder and then dropped the sub into a glass of water.
As the baking powder fizzed the small gas bubbles would cause it to rise to
the top of the glass, turn over, release the gas bubbles and sink again. The sub
may not have been edible but the principle is the same.
Peterborough, Cambridgeshire
